CAPSAICIN for Painful diabetic peripheral neuropathy | Diabetic peripheral neuropathy

Inclusion criteria

• {"criterion_text":"- Written informed consent signed and dated"}
• {"criterion_text":"- Diabetes mellitus according to the American Diabetes Association criteria (2017), lasting ≥1 year"}
• {"criterion_text":"- Age: 18-80 years"}
• {"criterion_text":"- Presence of painful diabetic sensorimotor polyneuropathy (DSPN) as judged by the investigator lasting ≥6 months"}
• {"criterion_text":"- Presence of pain in the feet and/or ankle caused by painful DSPN as diagnosed by the investigator with an average or maximum NPRS of ≥4 points within 7 days before screening"}
• {"criterion_text":"- Presence of dysesthesia or paresthesia in the lower extremity caused by DSPN as diagnosed by the investigator lasting ≥6 months"}
• {"criterion_text":"- Presence of either i) neuropathic deficits in the lower extremity (reduced or absent achilles tendon reflexes, vibration sensation, temperature detection, pain perception, pressure sensation), ii) ≥1 abnormal nerve conduction study parameter in lower extremity peripheral nerves (reduced or not evoked peroneal or tibial motor nerve conduction velocity or sural sensory nerve conduction velocity or amplitude), iii) ≥1 abnormal quantitative sensory test at the lower extremity (temperature detection threshold, vibration perception threshold), or iv) reduced intraepidermal nerve fiber density at screening"}
• {"criterion_text":"- HbA1c <10% at screening"}
• {"criterion_text":"- If applicable, stable regimen of glucose-lowering and analgesic treatment for DSPN within 4 weeks prior to screening as judged by the investigator"}
• {"criterion_text":"- Willingness to maintain current analgesic treatment unchanged during the course of the study"}
• {"criterion_text":"- Ability and willingness to meet the study center visits and to undergo study procedures during the whole study duration"}
• {"criterion_text":"- If applicable, willingness to take acceptable contraceptive measures by female participants in childbearing potential during the treatment phase"}
• {"criterion_text":"- If applicable, negative urine pregnancy test by female participants in childbearing potential at screening"}

Exclusion criteria

• {"criterion_text":"- Presence of pain caused by other conditions not clearly differentiated from pDPN as judged by the investigator"}
• {"criterion_text":"- Conditions that might interfere with the assessment of pDPN as judged by the investigator"}
• {"criterion_text":"- History of foot ulcers within the last 6 months prior to screening"}
• {"criterion_text":"- History of amputations at the lower extremity excluding minor amputations due to traumatic events not related to diabetic foot syndrome"}
• {"criterion_text":"- Treatment with Capsaicin 179 mg/8% patch within the last 6 months prior to screening or with any other topical analgesic pain treatment on the areas affected by neuropathic pain due to painful DSPN within the last 3 months prior to screening."}
• {"criterion_text":"- Concomitant analgesic treatment for painful DSPN with more than two substances, with medium or high potency opioids, or with electrical stimulation within the last 3 months prior to screening."}
• {"criterion_text":"- Substantial change in analgesic treatment regimen during the study as judged by the investigator"}
• {"criterion_text":"- Contraindications, known allergy, or hypersensitivity to capsaicin or other ingredients of the study medication or local anesthetics"}
• {"criterion_text":"- Average daily pain level ≥9 points NPRS within 7 days before screening"}
• {"criterion_text":"- Intraepidermal nerve fiber density at screening <1 fiber/mm"}
• {"criterion_text":"- Treatment with coumarins or heparin in a therapeutic dose or other contraindications against obtaining skin biopsies at the distal calf"}
• {"criterion_text":"- Pregnant women or nursing mothers"}
• {"criterion_text":"- Participation in another clinical trial study within the last 3 months prior to screening"}
• {"criterion_text":"- Neoplasms, except for basal cell carcinoma (basalioma) or low-grade prostate cancer within 12 months prior to screening"}
• {"criterion_text":"- Currently active or history of alcohol use disorder (>24 units of alcohol per week) or other substance-use disorders as judged by the investigator within the last 5 years"}
• {"criterion_text":"- Uncontrolled high blood pressure (DBP >95 mmHg and/or SBP >160 mmHg), unless clearly documented to be white-coat hypertension, at screening"}
• {"criterion_text":"- Severe resting tachycardia (HR >110 bpm) at screening"}
• {"criterion_text":"- Mental, psychiatric or other conditions compromising data collection or understanding of written or oral instructions during the study"}

Primary endpoints

• {"endpoint_text":"- Change from Baseline in IENFD (PGP9.5) at site with repeated treatment at Week 35 compared to placebo (primary endpoint)","definition_or_measurement_approach":"Change from baseline in intraepidermal nerve fiber density (IENFD) measured by PGP9.5 immunostaining at the treated site, assessed at Week 35 versus placebo."}

Secondary endpoints

• {"endpoint_text":"- Change from Baseline in IENFD (GAP-43), IENFL and DNFL (PGP9.5, GAP-43) at site with repeated treatment at Week 35 compared to placebo","definition_or_measurement_approach":"Change from baseline in IENFD markers (GAP-43, PGP9.5) and related nerve fiber length measures at Week 35 versus placebo."}
• {"endpoint_text":"- Change from Baseline in NPRS, PDQ7, NPSI, TSS, NSS, and MOS-12 at Week 11, Week 25, and Week 35 compared to placebo","definition_or_measurement_approach":"Change from baseline in patient-reported pain and symptom scales (NPRS, PDQ7, NPSI, TSS, NSS, MOS-12) at specified timepoints vs placebo."}
• {"endpoint_text":"- Change from Baseline in LDF and tissue oxygenation at standard and treated sites at Week 11 and Week 35 compared to placebo","definition_or_measurement_approach":"Change from baseline in laser Doppler flux (LDF) and tissue oxygenation measurements at treated and standard sites at Week 11 and Week 35 vs placebo."}
• {"endpoint_text":"- Change from Baseline in QST and monofilament at standard and treated sites at Week 11 and Week 35 compared to placebo","definition_or_measurement_approach":"Change from baseline in quantitative sensory testing (QST) and monofilament testing at specified sites/timepoints vs placebo."}
• {"endpoint_text":"- Change from Baseline in IENFD, IENFL and DNFL (PGP9.5, GAP-43) at Week 11 and Week 35 (at site with single treatment only) compared to placebo","definition_or_measurement_approach":"Change from baseline in nerve fiber density and length markers measured by PGP9.5 and GAP-43 at Weeks 11 and 35 for single-treatment sites vs placebo."}
• {"endpoint_text":"- Change from Baseline and from Week 10 in skin biopsy CD31 area and CD31-PGP9.5 at sites with single and repeated treatment at Week 35 compared to placebo","definition_or_measurement_approach":"Change from baseline and Week 10 in skin biopsy vascular marker CD31 area and CD31-PGP9.5 colocalisation at Week 35 vs placebo."}
• {"endpoint_text":"- Proportion of participants with an improvement in NPRS, PDQ7, NPSI, TSS, and NSS items reflecting the intensity of general pain, burning pain, pressing pain, paroxysmal pain, evoked pain, dysesthesia, and paresthesia, if present at baseline, compared to placebo at end of study","definition_or_measurement_approach":"Proportion achieving clinically meaningful improvements in specified pain/symptom items on the listed scales at end of study vs placebo."}
• {"endpoint_text":"- Number and severity of treatment-emergent AEs and the frequency of AEs leading to discontinuation, number of SAEs compared to placebo","definition_or_measurement_approach":"Safety assessments: counts and severity grading of TEAEs, AEs leading to discontinuation, and SAEs compared between groups."}
• {"endpoint_text":"- Proportion of participants who need rescue medication, frequency and amount of rescue medication, and time to first intake of rescue medication since randomization compared to placebo","definition_or_measurement_approach":"Proportion and timing of rescue medication use, frequency and amount, and time-to-first intake since randomization compared between arms."}

Methods

• Online recruitment questionnaire (document 'Online recruitment questionnaire') — digital self-report screening tool available to potential participants (Germany).
• Q-HEAL patient flyer (document 'Q-HEAL patient flyer') — informational leaflet for potential participants (Germany).
• Recruitment and informed consent procedure document (document 'Q-HEAL recruitment and informed consent procedure') — outlines site recruitment workflow (Germany).

Germany

Earliest CTIS Part Ii Submission Date

13-01-2026

Latest Decision Or Authorization Date

20-01-2026

Processing Time Days

7

Number Of Sites

2

Number Of Participants

40

Primary sponsor

Full Name

Deutsche Diabetes Forschungsgesellschaft e.V.

Organisation Type

Laboratory/Research/Testing facility

Country Of Registered Address

Germany

Third parties

• {"country":"","full_name":"Grünenthal GmbH","duties_or_roles":"Monetary support","organisation_type":""}